Copper is widely used in various fields of industry because of its high thermal and electrical conductivity and low price. In many cases, copper is used by itself, however, due to various reasons, in particular, like in the case of a heat sink, the use of copper mixed with carbon-based particles containing carbon as a main component, for example, graphite, SiC, carbon nanotubes, and the like, to form a composite material, is increasing.
In a carbon-based particle/copper composite material, the mixed state of carbon-based particles and copper is very important. When the mixed state of the two components is incompatible and the components exist separate from each other, it is impossible to obtain the material properties resulting from the complexation of the two components, and the mechanical properties reduce as well.
Because carbon-based particles and copper have different material properties, compatibility therebetween is poor. Conventionally, a liquid-phase sintering method, an impregnation method, and the like was used to prepare a carbon-based particle/copper composite material, but it was hard to achieve excellent compatibility of carbon-based particles and copper.